Antimicrobial and immunomodulatory activities of a peptide-rich preparation from Adenanthera pavonina seeds against multidrug-resistant β-haemolytic Staphylococcus aureus.

Abstract

Staphylococcus aureus (S. aureus) is notorious for antibiotic resistance and invasive infections. This study evaluated the antimicrobial and immunomodulatory properties of peptide-rich preparation from Adenanthera pavonina seeds (APSP) against multidrug-resistant β-haemolytic S. aureus. APSP was extracted using standard procedures, and its antimicrobial activity was evaluated using agar-well diffusion and killing kinetics assays. High-performance liquid chromatography identified its constituent amino acids, which were subjected to molecular docking against DNA gyrase B. The therapeutic effects of APSP were evaluated in vivo in seven groups (n = 4) of S. aureus-infected and APSP-treated Wistar rats. HPLC analysis identified arginine, proline, alanine, methionine, histidine, and isoleucine among the constituents. APSP demonstrated strong antimicrobial activity, producing a 22 mm inhibition zone at 100 mg/mL and a minimum inhibitory concentration of 25 mg/mL, with time-dependent reduction in bacterial counts. In vivo, APSP alleviated infection-associated symptoms and modulated PCV, WBC, and lymphocyte counts, particularly at 50 mg/kg. It also reduced ALT and AST levels without significant changes in ALP, while enhancing IgM and IgG responses. Additionally, APSP increased IFN-γ levels and modulated TNF-α and IL-6 in a dose-dependent manner. Overall, APSP demonstrated antimicrobial and immunomodulatory activities against multidrug-resistant S. aureus, supporting its potential as a candidate for further investigation in the management of infections caused by multidrug-resistant S. aureus.

Supplementary information: The online version contains supplementary material available at https://doi.org/10.1007/s40203-026-00757-7.